A preliminary assessment of impacts on estuarine associated fauna resulting from an intra-basin transfer and fresh water abstraction from aquatic systems in the Richards Bay area of KwaZulu-Natal, South Africa

An intra-basin transfer and the abstraction of water from aquatic systems in the Richards Bay area has led to the construction of six barriers which are restricting faunal movement, a reduction of flow to the Mhlathuze and Nhlabane estuaries and changes in the physico-chemical characteristics of four coastal lakes. These factors have severely impacted on the fauna of the aquatic systems in the area, particularly the fish but also the macrocrustacea and benthos. Preliminary results show that the structure of the interlinked marine-estuarine-river-coastal lakes ecosystem has been disrupted due to a cessation of migratory movements by the fauna which cannot cross the barriers. It is concluded that the construction of fishways will substantially contribute to reducing the current impacts and that the possibility exists that most will be in place within the next two to three years